(1) Field of the Invention
The present invention relates to an aircraft having at least one device for controlling inflation of an inflatable bag, commonly referred to as an “airbag”. Such a device is associated with a seat of an aircraft, such as for example an airplane, a rotorcraft, or indeed more particularly a helicopter. Thus, such a device serves to control inflation of an airbag likewise associated with the seat. In practice, such an airbag may be arranged by way of example on a safety harness that serves to hold an occupant of the aircraft in a sitting position on the seat, in particular in the event of an accident.
Consequently, each of the seats of the aircraft that is fitted with at least one airbag may include its own control device in accordance with the invention.
The invention also relates to an aircraft fitted with such a control device and to a method of controlling the inflation of an inflatable safety bag.
(2) Description of Related Art
In known manner, devices for controlling the inflation of an inflatable bag include control members having detector means for measuring the acceleration of the aircraft relative to at least one axis, and analysis means for identifying whether an accident of the aircraft is imminent. Where necessary, such analysis means then generate an order to inflate an inflation member in order to inflate the inflatable bag(s) of the aircraft seat.
Nevertheless, such control members need to be powered electrically and they consume a considerable quantity of electricity. Such electricity consumption can be problematic, since as a general rule, it is not possible to connect the control device of each seat electrically to a centralized source of electricity produced by the power plant of the aircraft.
Such a configuration may arise in particular in an aircraft when it is problematic to pass a wiring harness under the floor of the aircraft. By way of example, in rotorcraft in general, and in helicopters in particular, tanks for storing fuel are generally arranged immediately under the floor of the cabin and/or the cockpit.
Positioning and installing an electrical harness under the floor in order to power each of the seats of the aircraft would then have the consequence of reducing the available volume for storing fuel and/or of making the shape and the manufacture of fuel tanks more complex.
Furthermore, in order to power each control device via an electrical harness arranged under the floor of the aircraft, it would be necessary to provide a plurality of openings in the floor for passing electric cables for electrically powering the various control devices that are arranged above the floor. Such a plurality of openings would then have the effect of weakening the floor structure of the aircraft, which is problematic and would very likely require the thickness of the floor to be increased, and thus require its weight to be increased.
Thus, in order to avoid using an electrical harness for providing electrical power, it is possible for each of the seats to make use of an independent source of electricity, such as a battery.
Such batteries are then constantly connected to the control members and to the members for inflating the airbag(s). This results in a large amount of electricity being consumed. Such an arrangement then makes it necessary either to use batteries that are heavy and bulky but that present considerable operating lifetime, or else to undertake lengthy maintenance operations with short intervals between two operations, firstly for the purpose of verifying the level of charge in the batteries and secondly also for recharging them.
Furthermore, and as described in Document WO 99/15368, it is also known to reduce the electricity consumption of the control member for measuring an acceleration of an aircraft by connecting the source of electricity to the control device only while the buckles of the safety belt are connected together.
Nevertheless, such a solution consumes electricity for powering the control member as soon as the safety belts are buckled, and not only when a potentially dangerous situation has been identified by the control device.
In addition, and as described in Document EP 2 497 692 in the field of steering wheel airbags for motor vehicles, it is also known to use a first sensor continuously measuring a first current acceleration and a switch that is controllable as a function of the first current acceleration in order to activate and deactivate the control member.
Under such circumstances, a first low voltage electrical sensor acts continuously to detect the acceleration of the vehicle in a standby mode, and a second sensor acts occasionally to detect the acceleration of the vehicle only when a risk of an accident has been identified, which corresponds to an operational mode. Such a standby mode is used for the purpose of saving electricity consumption by the airbag control member by normally not making use of the second acceleration sensor to measure the acceleration of the motor vehicle.
Nevertheless, under such circumstances, the return from the operational mode to the standby mode, in which only the first sensor is in operation, takes place only after a predetermined duration. Such a solution is therefore not optimized in terms of limiting the electricity consumption of such a control system in the event of no risk of accident being detected. Specifically, such a solution is content to remain in the operational mode for a predetermined duration that is necessarily much longer than the occurrence of a risk of an accident, in order to be able to detect that risk.
Furthermore, Document DE 197 07 307 describes another device for controlling a motor vehicle airbag that has two acceleration sensors that are constantly powered electrically. Such a device thus consumes a particularly large amount of electricity and is therefore not adapted for use with a device for controlling inflation that is arranged on an aircraft seat.